This invention relates generally to display indicators, and more particularly to digital display indicators that simulate a seven-segment digital readout.
In many instances, it is desirable to simulate the font generated by a seven-segment display for aesthetic reasons or to provide a consistent character font when a mixed display of seven-segment and conventional displays are used. Several displays that either provide or simulate a seven-segment digital display are known. Such displays range from true seven-segment displays that utilize electronic displays such as neon tubes or luminescent semiconductors to simulated seven-segment displays that use mechanical devices such as masks and mechanically movable segments which generate a segmented display when viewed through the mask. Two such mechanical display units are described in U.S. Pat. Nos. 3,683,523 and 3,721,087. Other systems such as the systems described in U.S. Pat. Nos. 3,836,911; 3,889,196; and 3,918,392 utilize fiber optics to generate a digital display, and systems such as the one described in U.S. Pat. No. 3,916,317 use a mask system to generate a simulated fiber optics display.
While the electronic devices, such as the neon tubes or luminescent semiconductors provide an attractive and readable display that may be viewed without external lumination, the neon tubes require a relatively high voltage power source, not readily available from transistorized circuitry, and both require relatively complex logic circuitry for selecting the segments to be illuminated. The mechanical display devices avoid the need for the logic circuitry, but require relatively complex mechanical cams and linkages for properly positioning the segments to generate the desired numbers. These cams and linkages are relatively costly and subject to failure. The fiber optics systems also tend to be relatively costly and complex.